Transformer Design Principles

TRAMA

Completely revised, this second edition of a bestseller includes a general treatment of multi-terminal transformers, a unified discussion of oil electrical breakdown in various geometries, coverage of testing, life extension, and maintenance issues, and the use of 3D finite element calculations in design. The book presents the theory of transformers starting from first principles so that readers can understand the fundamentals of the formulas and procedures that are later developed for use in the design process and adapt the results to new developments as they occur. The book also emphasizes transformer model development, so that their performance under a variety of conditions can be determined.

NOTE EDITORE

Updating and reorganizing the valuable information in the first edition to enhance logical development, Transformer Design Principles: With Applications to Core-Form Power Transformers, Second Edition remains focused on the basic physical concepts behind transformer design and operation. Starting with first principles, this book develops the reader’s understanding of the rationale behind design practices by illustrating how basic formulae and modeling procedures are derived and used. Simplifies presentation and emphasizes fundamentals, making it easy to apply presented results to your own designs The models, formulae, and methods illustrated in this book cover the crucial electrical, mechanical, and thermal aspects that must be satisfied in transformer design. The text also provides detailed mathematical techniques that enable users to implement these models on a computer. The authors take advantage of the increased availability of electromagnetic 2D and 3D finite element programs, using them to make calculations, especially in conjunction with the impedance boundary method for dealing with eddy current losses in high-permeability materials such as tank walls. Includes new or updated material on: Multi terminal transformers Phasors and three-phase connections Impulse generators and air core reactors Methodology for voltage breakdown in oil Zig-zag transformers Winding capacitances Impulse voltage distributions Temperature distributions in the windings and oil Fault type and fault current analyses Although the book’s focus is on power transformers, the transformer circuit models presented can be used in electrical circuits, including large power grids. In addition to the standard transformer types, the book explores multi-terminal transformer models, which allow complicated winding interconnections and are often used in phase shifting and rectifying applications. With its versatile coverage of transformers, this book can be used by practicing design and utility engineers, students, and anyone else who requires knowledge of design and operational characteristics.

SOMMARIO

Introduction Historical Background Uses in Power Systems Core-Form and Shell-Form Transformers Stacked and Wound Core Construction Transformer Cooling Winding Types Insulation Structures Structural Elements Modern Trends Magnetism and Related Core Issues Basic Magnetism Hysteresis Magnetic Circuits Inrush Current Distinguishing Inrush from Fault Current Optimal Core Stacking Circuit Model of a Two-Winding Transformer with Core Circuit Model of the Core Two-Winding Transformer Circuit Model with Core Approximate Two-Winding Transformer Circuit Model without Core Vector Diagram of a Loaded Transformer with Core Per-Unit System Voltage Regulation Reactance and Leakage Reactance Calculations General Method for Determining Inductances and Mutual Inductances Two-Winding Leakage Reactance Formula Ideal Two-, Three-, and Multiwinding Transformers Leakage Reactance for Two-Winding Transformers Based on Circuit Parameters Leakage Reactances for Three-Winding Transformers Phasors, Three-Phase Connections, and Symmetrical Components Phasors Wye and Delta Three-Phase Connections Zig-Zag Connection Scott Connection Symmetrical Components Fault Current Analysis Fault Current Analysis on Three-Phase Systems Fault Currents for Transformers with Two Terminals per Phase Fault Currents for Transformers with Three Terminals per Phase Asymmetry Factor Phase-Shifting and Zig-Zag Transformers Basic Principles Squashed Delta Phase-Shifting Transformer Standard Delta Phase-Shifting Transformer Two-Core Phase-Shifting Transformer Regulation Effects Fault Current Analysis Zig-Zag Transformer Multi-terminal Three-Phase Transformer Model Theory Transformers with Winding Connections within a Phase Multiphase Transformers Generalizing the Model Regulation and Terminal Impedances Multiterminal Transformer Model for Balanced and Unbalanced Load Conditions Rabins’ Method for Calculating Leakage Fields, Leakage Inductances, and Forces in Transformers Theory Rabins’ Formula for Leakage Reactance Application of Rabins’ Method to Calculate the Self-Inductance of and Mutual Inductance between Coil Sections Determining the B-Field Determination of Winding Forces Numerical Considerations Mechanical Design Force Calculations Stress Analysis Radial Buckling Strength Stress Distribution in a Composite Wire-Paper Winding Section Additional Mechanical Considerations Electric Field Calculations Simple Geometries Electric Field Calculations Using Conformal Mapping Finite Element Electric Field Calculations Capacitance Calculations Distributive Capacitance along a Winding or Disk Stein’s Disk Capacitance Formula General Disk Capacitance Formula Coil Grounded at One End with Grounded Cylinders on Either Side Static Ring on One Side of Disk Terminal Disk without a Static Ring Capacitance Matrix Two Static Rings Static Ring Between the First Two Disks Winding Disk Capacitances with Wound-in Shields Multistart Winding Capacitance Voltage Breakdown and High-Voltage Design Principles of Voltage Breakdown Geometric Dependence of Transformer-Oil Breakdown Insulation Coordination Continuum Model of Winding Used to Obtain the Impulse-Voltage Distribution Lumped-Parameter Model for Transient Voltage Distribution Losses No-Load or Core Losses Load Losses Tank and Shield Losses Due to Nearby Busbars Tank Losses Associated with the Bushings Thermal Design Thermal Model of a Disk Coil with Directed Oil Flow Thermal Model for Coils without Directed Oil Flow Radiator Thermal Model Tank Cooling Oil Mixing in the Tank Time Dependence Pumped Flow Comparison with Test Results Determining m and n Exponents Loss of Life Calculation Cable and Lead Temperature Calculation Tank Wall Temperature Calculation Tieplate Temperature Core Steel Temperature Calculation Load Tap Changers General Description of Load Tap Changer Types of Regulation Principles of Operation Connection Schemes General Maintenance Miscellaneous Topics Setting the Impulse Test Generator to Achieve Close to Ideal Waveshapes Impulse or Lightning Strike on a Transformer through a Length of Cable Air Core Inductance Electrical Contacts References Index

AUTORE

Robert M. Del Vecchio received the BS degree in physics from the Carnegie Institute of Technology, Pittsburgh, Pennsylvania, the MS degree in electrical engineering, and the Ph.D. degree in physics from the University of Pittsburgh in 1972. He was a Lecturer in physics at Princeton University, New Jersey, from 1972 to 1976, and an Assistant Professor at the University of Pittsburgh from 1976 to 1978. He then joined the Westinghouse R&D Center, Pittsburgh, where he worked on modeling magnetic materials and electrical devices. He joined North American Transformer (now Waukesha Electric Systems) in 1989, where he developed computer models and transformer design tools. He is a member of the IEEE Power and Energy Society and Magnetics Society. He has served on the IEEE Transformers Committee, the IEC, and a Cigre committee. Currently, he is a consultant. Bertrand Poulin received his Bachelor of Engineering degree in Electrical Engineering from École Polytechnique Université de Montréal in 1978 and his MS degree in High Voltage Engineering in 1988 from the same University. Bertrand started his carreer in a small repair facility for motors, generators and transformers in Montréal in 1978 as a technical advisor. In 1980, he joined the transformer division of ASEA in Varennes, Canada as a test engineer and later as a design and R&D engineer. In 1992, he joined North American Transformer where he was involved in testing and R&D and finally manager of R&D and testing. In 1999, he went back to ABB in Varennes where he holds currently the position of Technical Manager for the Varennes facility and Senior Principal Engineer for the Power Transformer Division of ABB worldwide. He is a member of IEEE Power and Energy Society, an active member of the Transformers Committee, and a registered Professional Engineer in Québec, Canada. Pierre Feghali, PE, MS received his bachelor’s degree in Electrical Engineering from Cleveland State University in 1985 and his Master's degree in Engineering Management in 1996 from San Jose State University. He has worked in the transformer industry for over 23 years. He started his career in distribution transformer design at Cooper Power Systems in Zanesville, Ohio. In 1989, he joined North American Transformer in Milpitas, CA where he was a Senior Design Engineer. Between 1997 and 2002, he held multiple positions at the plant including: production control manager, quality and test manager, and plant manager. He is currently Vice President of Business Development and Engineering at North American Substation Services, Inc. He is a Professional Engineer in the state of California and an active member of the IEEE and PES. Dilipkumar M. Shah received his BSEE degree from the M.S. University of Baroda (India) in 1964 and his MSEE degree in Power Systems from the Illinois Institute of Technology (Chicago, Illinois) in 1967. Since 1967 until 1977, he worked as a transfomer design engineer at Westinghouse Electric, Delta Star, and Aydin Energy Systems. He joined North American Transformer in 1977 as a senior design engineer and then the engineering manager. He left in 2002 and has been working as a transformer consultant for utilities world wide, covering areas such as design reviews, diagnosing transformer failures, and advising transformer manufacturers on improving their designs and manufacturing practices. Rajendra Ahuja graduated from the Univ. of Indore in India where he received a B.Engg. Hons. (Electrical) degree in 1975. He worked at B.H.E.L. and GEC Alsthom India and was involved in design and development of EHV transformers and in the development of wound-in-shield type windings. He also has experience in the design of special transformers for traction, furnace, phase shifting, and rectifier applications. He joined North American Transformer (now Waukesha Electric Systems) in 1994 as a principal design engineer and became the manager of the testing and development departments. He is currently the vice president of engineering. He is an active member of the Power and Energy Society, the IEEE Transformers Committee, and the IEC.

ALTRE INFORMAZIONI

• Condizione: Nuovo
• ISBN: 9781439805824
• Dimensioni: 9.25 x 6.25 in Ø 2.25 lb
• Formato: Copertina rigida
• Illustration Notes: 285 b/w images, 34 color images, 36 tables and 1450-1550 equations
• Pagine Arabe: 636